Appalling mileage but great car!

[petefeet]

Evening all
Just thought I'd log on and see what was happening here. I've just bought myself a S2 avant on an M plate (ebay early december) and while its a great, smooth fast car, I can't quite believe the mpg its doing; 16.7 on the dash. I've also got a MX5 (just for fun mind) and a chipped GT TDI which can do 50 or 25 depending on how its driven.

Now I bought this to cart two dogs around and we're off to Ireland at Easter but with this mileage I'll have to fill up between here and Pembroke Dock which can't be right. Especially at 1 in the morning - the boat leaves at 2.45am. The original spec mentions 25mpg overall with a 30 possible but I never see that even crawling along. So my guess (after check the forums) is check the lambda, the cylinder head sensor and the MAF and then bung some cleaner in the tank and see what happens.

Oh, and thanks to Dave and Rich who came to see the car when I was selling it soon after buying it (partner didn't like it) and convinced me to keep it. After a bit of work at QS Tuning its come alive!
pete

[Greg_S]

Welcome to the forum pete, mpg assuming that it is a stock motor on a run 28-30mpg should be achieveable. Around town it goes down quite a bit though.

Good luck getting it sorted.

[Jay]

big turbo

Fit a larger turbo and gain mpg, win win with that one!!

Jay

[Rusty]

Mine's standard and I see 17-19 around town and 25-27 on a motorway cruise. Average over my ownership IIR 22mpg. You can get more out of it but it takes too much effort and is really boring!

You've got the right course of action:

New Lambda is a good start - Easy job and a genuine Lambda probe is in the region £65+vat from VAG Parts IIRC. Bosch branded ones are available cheaper - same part.

Clean the MAF. IPA or I just use carburettor cleaner .

Run it on premium fuel - Esso supreme is my favourite as it's cheaper than Shell V-Power. BP Ultimate isn't that great, same for Tesco 99 but still better than 95. This should improve power and MPG as a standard car is much more at home with 98 IMHO. Obviously this is a false economy as you spend more and use less!

Check the running temperature. Under 80deg C in this cold weather puts the ECU into cold start mode and can cause poor MPG. Replacing the thermostat solved this problem for me, diagnosed during a visit to MRC.

Fit a boost gauge with vacuum reading. It's amazing how much you can throttle back and still maintain the same speed and also you can prevent the car going into boost by throttling back during acceleration. his works, my Dad has achieved 28+MPG oput of mine over a week (not a chance with my driving!). My boost gauge is a TIM item, cheap but does the job and has a useful green, yellow & red colour coding, green = best MPG red = FUN

Not so sensible but still sound ideas are:

Fit a freer flowing exhaust! I noticed a slight difference when I fitted a Miltek cat back system. 5% or so overall, more on a cruise.

Get a remap or homefries chip! You'll see better MPG on a cruise but then completely destroy all the hard work on the twisty bits or with a traffic light GP!

Get a bigger turbo. Reduced back pressure in the exhaust reduces pumping losses of the engine and improves efficiency. Gets my vote! MPG may degrade due to grin factor though!

HTH

[petefeet]

thanks for that; i did have a new thermostat fitted but the temp gets to around 80 ish and stays there so its not that.
the lambda sounds easy so i'll stick a new bosch one in and a set of plugs and see if that helps

and is there a link for the boost guage job?

btw, the car is standard so i was hoping to get 25 ish at least. Surely even a porsche gets that if you're careful?!

the other stuff (big turbo etc) i'm not so sure about - i might just inflate the tyres to 50psi to reduce rolling resistance!
pete

[LHD_Kid]

Normal running temp. for the car is 90....
Might still be this that is the problem... I read many posts on how Audi might have calibrated the graduation marks on the temp. gauge, its a bit daft... but anyway... it really needs to run at 90, could be the MFTS in the water manifold...
I changed mine and solved a curious temperature fluctuatuion problem...
Not expensive, but a real pain of a job....

[Rusty]

You'll get 25 average if you do lots of motorway driving but no chance in town or stop-start driving. I don't even bother caring anymore, it's too depressing listening to all the diseasel drivers talking about numbers beginning with fourty and fifty...

[4WheelDrifter]

I can get ~30mpg at a constant 70mph on V-Power, but only 27mpg on BP Ultimate 97, and 23mpg on Sainsbury's 95.
Well, I had to try 95 RON fuel once, just to see what it was like. Never again.
Long trips normally average ~25mpg. Genaral driving about returns ~21mpg. I'm not sure about city driving, I try not to do that.

[phil2.016v]

Mines's doin 13 at the mo on Total excellium (or however you spell it!).

That's round town, about a 1 mile round trip

[Rusty]

Do you have any cities near you Stu?!?

Remap, big turbo, 3" turbo back and a reverse inlet should see an improvenent... that's my reasoning

[rj scotty]

Mines's doin 13 at the mo on Total excellium (or however you spell it!).

That's round town, about a 1 mile round trip

thats about my leval

[leeboy]

i had a recent binding brake problem on my rears, was doing about 22 on a run, now im doing around 27 woohoo lol. Still only seeing about 19-20 round town. Even with my brake problem she still pulled 262 on the dyno

[Rusty]

Paul claims better mpg off a homefries that a standard map.

[BrianSmith_S2]

Paul claims better mpg off a homefries that a standard map.

yep, all that extra torque from a remap or homefry helps the mpg on light throttle .

use of a heavy right foot makes it worse thou, but so much more fun.lol